So what’s a good hash function? • Heuristic, good when keys are uniformly distributed! • Idea! Don’t use a fixed hash function! Choose one randomly (but carefully)! Universal (good, theoretically): • Why is …

Hashing is used in cryptography for secure (encrypted) communication and maintaining data integrity. For example, when you communicate over a WiFi network: Is this website secure?

An O(n) space solution (for static S) First, hash all values in S into a table of size n using universal hashing.

Understand the formal definition and general idea of hashing Define and analyze universal hashing and its properties Analyze an algorithm for perfect hashing

Chaining: All keys that map to the same table location are kept in a list (a. a “chain” or “bucket”) As easy as it sounds Example: insert 10, 22, 107, 12, 42 with mod hashing and TableSize

Up to Java 8, HashMap handles collision by using a linked list to store map entries ended up in same array location or bucket location. From Java 8 onwards, HashMap uses a balanced tree in place of …

Hashing: basic plan Save items in a key-indexed table (index is a function of the key)